1. Field
The present disclosure relates to inner focus lens systems, interchangeable lens apparatuses and camera systems.
2. Description of the Related Art
Interchangeable lens apparatuses, camera systems and the like, each including an image sensor for performing photoelectric conversion, are strongly required to achieve size reduction and performance improvement. Various kinds of lens systems used in such interchangeable lens apparatuses and camera systems have been proposed.
Japanese Laid-Open Patent Publication No. 2012-027349 discloses an inner focus lens system including a first lens unit having positive refractive power, a second lens unit, and a third lens unit having positive refractive power. In focusing from an infinity in-focus condition to a close-object in-focus condition, the first lens unit is fixed with respect to an image surface, the second lens unit moves along an optical axis, and the third lens unit is fixed with respect to the image surface.
Japanese Laid-Open Patent Publication No. 2012-189679 discloses an inner focus lens system including a first lens unit having positive refractive power, a second lens unit, and a third lens unit. In focusing from an infinity in-focus condition to a close-object in-focus condition, the first lens unit is fixed with respect to the image surface, the second lens unit moves along the optical axis, and the third lens unit is fixed with respect to the image surface.